package com.lwz.web.util;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

import javax.servlet.http.HttpSession;
import java.util.Date;
import java.util.HashMap;

/**
 * 用于创建token信息类
 * @author Lw中
 * @date 2020/9/1 16:27
 */
public class JwtTokenUtils {

    public static HttpSession httpSession;

    public static final String TOKEN_HEADER = "Authorization";
    public static final String TOKEN_PREFIX = "Bearer ";
    /**秘钥*/
    private static final String SECRET = "jwtSECRET";
    /**签发者*/
    private static final String ISS = "long";
    /**角色的key*/
    private static final String ROLE_CLAIMS = "rol";
    /**过期时间是3600秒，既是1个小时*/
    private static final long EXPIRATION = 3600L;
//    // 选择了记住我之后的过期时间为7天
//    private static final long EXPIRATION_REMEMBER = 604800L;

    /**
     * 创建token
     * @param username
     * @param role
     * @return
     */
    public static String createToken(String username, String role) {
        long expiration = EXPIRATION;
        HashMap<String, Object> map = new HashMap<>();
        map.put(ROLE_CLAIMS, role);
        String token = Jwts.builder()
                .signWith(SignatureAlgorithm.HS512, SECRET)
                .setClaims(map)
                .setIssuer(ISS)
                .setSubject(username)
                .setIssuedAt(new Date())
                .setExpiration(new Date(System.currentTimeMillis() + expiration * 1000))
                .compact();
        return token;
    }

    /**
     * 从token中获取用户名
     * @param token
     * @return
     */
    public static String getUsername(String token) {
        return getTokenBody(token).getSubject();
    }

    /**
     * 获取用户角色
     * @param token
     * @return
     */
    public static String getUserRole(String token) {
        return (String) getTokenBody(token).get(ROLE_CLAIMS);
    }

    /**
     * 获取用户角色
     * @param token
     * @return
     */
    public static boolean isExpiration(String token) {
        return getTokenBody(token).getExpiration().before(new Date());
    }

    private static Claims getTokenBody(String token) {
        return Jwts.parser()
                .setSigningKey(SECRET)
                .parseClaimsJws(token)
                .getBody();
    }

}
